The Most Elusive Color in Chemistry Might Surprise You

Seeing a color in nature is one thing. Recreating colors artificially is an entirely different challenge—one with some unexpectedly high stakes.

Practically anything human-made is of a certain color thanks to artificial pigments, or chemical compounds that appear a specific color. An ongoing challenge is that, as chemical bonds naturally fade, so does the color. This won’t be an issue for most painting tasks, but for more high-quality products like Ferraris, preventing this loss of color can get seriously costly.

And then there’s the color red, which, for structural reasons, is generally difficult to achieve in chemistry. For practical purposes, therefore, the most difficult color to artificially create is a brilliant and durable shade of red—one that can withstand time and natural forces. Hence, a “perfect red.â€

A recent New Scientist article profiled Mas Subramanian, a material scientist at Oregon University who discovered a novel type of artificial blue. Now, Subramanian is trying to arrive at the perfect red. The profile, which I highly encourage you to read, brings renewed attention to pigment chemistry—a research field that, despite its importance across countless industries, remains oddly enigmatic.

To put this in perspective, “many companies†have reportedly told Subramanian that cracking the code for the perfect red pigment would make him a billionaire. Indeed, in pigment chemistry, not all colors are created equal—and the reason comes down to some easily overlooked, yet very cool, science.

The chemistry of hues

Color emerges from the way light interacts with electrons inside molecules. When light strikes a molecule, it powers up the electrons, making them jiggle up to a higher energy level. But these transitions depend on the physical structure of the molecule, as these geometries regulate which wavelengths of light are absorbed and reflected.

Accordingly, in pigment chemistry, finding the right element isn’t as important as identifying which arrangement gives off the desired color. For instance, what gives emeralds and rubies their respective green and red colors is the same element, chromium, just with a different atomic arrangement.

Historically, colors were “discovered†more organically, as ancient artists landed on color recipes combining minerals, animal fats, etc., to create paints and inks. One famous example is Egyptian blue, which ancient Egyptians manufactured using sand, sodium carbonate, and copper or bronze shavings.

A chemist’s color hack

Subramanian’s claim to fame was the discovery of “YInMn Blue,†which is as close as one gets to a “perfect†blue (hex code #0000ff). Fascinatingly, the pigment’s structure—a distorted double pyramid—is intentionally asymmetrical, which scales back quantum rules that forbid electrons from jumping between particular energy levels.

These discoveries have huge practical applications. Laurie Pressman, vice president of the Pantone Color Institute, told Bloomberg that the right chemistry allows manufacturers to “create the blue in velvet, silk, cotton, rayon, or coated paper stock.â€

“It’s not just the color,†Pressman added. “It’s the chemical composition of the color. And can that composition actually be realized in the material I’m going to apply it to?â€

The billion-dollar pigment

If you have even an inkling of interest in art history, you probably know that red is definitely not “rare†in paintings. Heck, the earliest known painting had streaks of red. But none of these are “perfect†reds, in the sense that organic red pigments are chemically fragile and fade too easily.

And in 2020, the NSF gave Subramanian a $200,000 grant to find a solution. The chemist hasn’t gotten there yet, although he and his team allegedly achieved a “reddish-magenta†and other orangish colors. To New Scientist, Subramanian explained that electron transitions between the relevant energy levels “rarely yield a clean, bright red.â€

The team has also played around with semiconductor additions that also absorb light. But Subramanian admitted that they are still “somewhat playing the dice.â€

As someone fairly well-versed in art and color theory, I found YInMn Blue to be absolutely beautiful. The distinction between different shades of the same color might seem trivial, but I genuinely couldn’t identify an existing color (in the realm of artificial pigments) with the same brilliance. Not only that, it’s meant to be usable in everyday products!

So personally, I’m really looking forward to the pleasant surprise that’s in store with “perfect red.†I hope they find the right atomic recipe in my lifetime.